1. Technical Field
The present invention relates to a droplet ejection apparatus.
2. Background Art
In an ink jet recording apparatus, which is one type of droplet ejection apparatus, when its power is turned off by a key switch, sequence to carry out a cap operation (capping) before the power off is adopted in order to prevent a high quality printing operation from not being carried out due to drying of ink within and in the vicinity of an ejection port by leaving a recording head without capping. In order to achieve this capping operation, the processing in which a pseudo power-off state is established (although an electric current constantly flows to a control system, it is called the “power-off state”) is carried out.
However, in this conventional method, in the case where power supply to the apparatus is stopped without a power-off operation of the key switch, for example, in the case where a power cord thereof is accidentally yanked or power failure is broken out, it is impossible to protect the ejection port of the recording head, and there is a problem that clogging of the ejection port (nozzle) may occur.
Further, although the ink jet recording apparatus is in the power-off state, a predetermined recovery operation is carried out when the apparatus is powered on again. Hence, it is not necessarily that an optimum recovery operation is carried out, and there are any defects that the amount of ink more than needed is consumed or it takes a lot of trouble that the recovery operation is manually carried out by a user of the apparatus because the recovery operation carried out is unsatisfactory.
As solutions to these defects, in order to prevent a incomplete capping operation at the cutoff of the power, an apparatus provided with a standby power supply capable of supplying a power to the apparatus for a time required to carry out the capping operation surely is proposed (for example, Japanese Laid-Open Patent Application No. 20008-351204 or the like).
However, even though the complete capping operation was carried out, a degree of ink viscosity may be increased due to vaporization of a solvent in the ink (for example, water in the case of water-soluble ink) through the ejection ports of the recording head (hereinafter, it is also referred to as “thickening ink”). Further, as described above, although the ink jet recording apparatus is in the power-off state, a predetermined recovery operation is carried out when the apparatus is powered on again. Hence, it is not necessarily that an optimum recovery operation is carried out.